Billions of T-Cells Clear Woman's Breast Cancer in Study

(Bloomberg) -- An experimental therapy that extracts and multiplies powerful immune-system cells from inside tumors eradicated a patient’s breast cancer, a scientific first that could lead to new ways of treating malignancies that have resisted all other efforts.

Researchers at the U.S. National Cancer Institute gave the experimental treatment, which has since been licensed to Gilead Sciences Inc., to a 49-year-old woman whose cancer came roaring back after a decade in remission. The woman had tennis-ball-sized tumors in her liver and growing through her chest wall. Despite seven types of chemotherapy and hormonal therapy, her disease was still growing.

Using a biopsy, researchers plucked rare cells custom-made by the immune system from inside tumors, but in numbers too small to help a patient on their own. They grew copies of the cells in the lab, multiplying them into billions over a period of weeks. They were then infused back into the patient.

Two-and-a-half years after getting the new cells, the woman is cancer-free. The method, while still in its infancy, also shrank hard-to-treat tumors in six other patients with colon and cervical cancers, said Steven Rosenberg, chief of surgery at the National Cancer Institute where it is being studied.

“They are attacking their own cancers,” Rosenberg said in an interview. “It’s as highly personalized as a treatment can be. We are creating a new drug for every patient, targeting the unique mutations in that same patient’s cancer.”

Gilead’s Kite unit signed a development agreement for the experimental therapy, Rosenberg said. The Foster City, California-based company is building out a pipeline of cancer drugs after years of success with treating viral infections such as hepatitis and HIV.

Gilead shares gained as much as 3.7 percent on Monday, and were up 1.9 percent to $69.60 at 11:16 a.m. in New York.

The results were published Monday in the scientific journal Nature Medicine.

Custom Therapy

So far, the researchers have treated 40 patients, all with types of tumors that account for 80 percent of cancer deaths, according to Rosenberg. Seven have responded to the therapy.

It took about eight weeks to craft the therapy for the breast-cancer patient. Six weeks after getting it, the amount of cancer in her body had shrunk by half. Two and a half years later, all signs of her cancer have disappeared.

The immunotherapy field has seen major breakthroughs in the past year, including the approval of two so-called CAR-T treatments from Gilead and Novartis AG that extract T-cells from a patient’s blood and re-engineer them to recognize malignancies. Drugmakers have had less success using that technique on widespread solid tumors.

Inside the Tumor

Rosenberg’s team takes a different tack. The researchers isolate rare T-cells that each patient produces in response to unique mutations that fuel the development of their cancer. Minute amounts of these natural T-cells infiltrate the tumor, though they aren’t present in high enough quantities to combat the growing cancer, Rosenberg said.

After extracting the tumor-infiltrating lymphocytes from a biopsy, his team can multiply the cells and give billions of them back to the patient.

The group is getting better at identifying the rare T-cells that can attack the tumor, finding three times more of them in samples than they were even three months ago, Rosenberg said. There is still a long way to go, he said, but it’s an approach that isn’t specific to a certain cancer type, meaning it could evolve into an effective therapy for many forms of the disease, he said.

“Part of the excitement is because all cancers contain mutations, it’s a technique that could potentially be applied to any tumor type,” Rosenberg said. “It opens the door to the treatment of almost any cancer.”

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